Tips for combining bedrooms with nursery?

We live in a 3 bedroom rental house and will have to combine the nursery with either our bedroom or our 4 year old daughters. Our 13 month old son's room is too small to share. Any BTDT moms have any tips for cute ways to room share? At this point I am not even sure if the two girls would be able to room share until the baby is older--what age would be appropriate to put the baby in with her big sister? (I'm sort of nervous to leave a young child unattended with an infant even at night--my dd is amazing and loving but I just don't know if that's a safety issue?) Or we could just put the crib in our bedroom since we have room--but then is there a way to make it feel like the baby has her own space? Sorry if this is a dumb question, I just don't know how the logistics will work...

We live in Virginia right outside of DC and all of the houses around here are old and small. Well, unless you are very wealthy (which we are not, lol). We live in a small two bedroom two bath. I have a son who is 12 and totally not willing to share his cool room with his new baby sister. So we made a space in our little room for her. We purchased a mini crib that has attached drawers at the side and bottom. We painted the wall that the crib sits on pink and added a decal and it looks amazing. It was definitely not my first choice but it worked. Let me know if you would like to see pics. Wish I could attach them to my comment.

I am in the same situation, sort of. I have a 10yr old son, 7yr old daughter and having a boy. We decided to put the crib and changing table in our room and have him share part of our closet until he is big enough to sleep in our sons room (which is large enough). I am not sure what age is appropriate, I guess it would depend on the children. Our son is super calm and sweet at 10..I guess possibly when the baby is mature enough to sleep in his own bed?

In the meantime, we put his crib againist the wall and decorated the wall above, the changing table is directly across from his crib on the opposite wall, I bought large storage bins and put all his clothes, diapers, etc in there under the changing table area becuase I am short on dresser space. You can tell that those parts of the room are officially baby and not ours anymore.

^ How funny, OUR 12 year old DS refuses to share his cool space with his 9 year old little brother and would rather have a new baby in his room! We are putting the baby girl in our room..see my profile for pics..not so great but gives you an idea.

I have a nine year old son and five year old daughter who share a room now. We are planning on getting a bunked for the older ones and when it's time for the baby to move into a crib, after six months or when the baby starts to roll over in the bassinet, will go into the kids room. Will decorate the wall the crib is on. This is the plan but it all depends on the sleep patterns of the baby and if the other two will be harshly disrupted.